Celebrities have long contended with the occasional downsides of stardom - tabloid scandals, stalkers, box office bombs, the paparazzi. Now, add "swatting" to the list - a prank that sends police charging to the gates of stars' homes on false reports of gunmen, hostages or other crimes in progress.

Instead of bad guys, responding officers, police dogs, helicopters and sometimes SWAT teams have found only stunned domestic and security staff unaware of any trouble - because there wasn't any.

The recent hoax 911 calls to the homes of Tom Cruise, Justin Bieber, Ashton Kutcher, Chris Brown and other stars are leading authorities to eye some 911 calls with extra suspicion and lawmakers to call for stiffer penalties for the pranksters.

"This is a very vexing problem that needs to be fixed at the early stages," said state Sen. Ted Lieu, D-Torrance (Los Angeles County), who is proposing tough penalties, including hefty fines, for those caught swatting. "If this isn't resolved, this will result in a tragic situation."

Swatting is the rare trend that actually didn't start in Hollywood. Authorities in Dallas, Washington state, Alabama and elsewhere have arrested teens and young men for bogus 911 calls that have drawn large police responses and in some cases, resulted in innocent people being detained by police.

The term comes from the pranksters' desire to have heavily armed special weapons teams dispatched to their calls. That doesn't always happen, but the calls tie up resources ranging from dispatchers, patrol officers, helicopters, detectives and cybercrime specialists.

The Beverly Hills Police Department estimated more than half of its emergency resources were occupied with the Cruise swatting call on Jan. 17. It was just one of a rash of calls aimed at celebrities over the next several days, including a false claim there was a domestic violence incident at Brown's home.

"We're getting much better at deciphering what is real and what is not," said Steve Whitmore, a spokesman for the Los Angeles County Sheriff's Department. The agency has handled calls to Bieber's home and a former Kardashian family home.

The California bill would increase the penalties for convicted swatters to up to three years in jail if someone was hurt as a result of their call, and also make them responsible for the costs of the emergency response.